Input: libps2 - warn instead of oopsing when passed bad arguments

[firefly-linux-kernel-4.4.55.git] / drivers / input / serio / libps2.c

diff --git a/drivers/input/serio/libps2.c b/drivers/input/serio/libps2.c
index 92b92ee0379177d291e01c829f94a11e6f34cdf8..ed202f2f251aa76eeb3b680186a7baa7ddefaa7a 100644 (file)
--- a/drivers/input/serio/libps2.c
+++ b/drivers/input/serio/libps2.c
@@ -84,7 +84,7 @@ void ps2_drain(struct ps2dev *ps2dev, int maxbytes, int timeout)
                maxbytes = sizeof(ps2dev->cmdbuf);
        }
 
-       down(&ps2dev->cmd_sem);
+       mutex_lock(&ps2dev->cmd_mutex);
 
        serio_pause_rx(ps2dev->serio);
        ps2dev->flags = PS2_FLAG_CMD;
@@ -94,7 +94,67 @@ void ps2_drain(struct ps2dev *ps2dev, int maxbytes, int timeout)
        wait_event_timeout(ps2dev->wait,
                           !(ps2dev->flags & PS2_FLAG_CMD),
                           msecs_to_jiffies(timeout));
-       up(&ps2dev->cmd_sem);
+       mutex_unlock(&ps2dev->cmd_mutex);
+}
+
+/*
+ * ps2_is_keyboard_id() checks received ID byte against the list of
+ * known keyboard IDs.
+ */
+
+static inline int ps2_is_keyboard_id(char id_byte)
+{
+       static char keyboard_ids[] = {
+               0xab,   /* Regular keyboards            */
+               0xac,   /* NCD Sun keyboard             */
+               0x2b,   /* Trust keyboard, translated   */
+               0x5d,   /* Trust keyboard               */
+               0x60,   /* NMB SGI keyboard, translated */
+               0x47,   /* NMB SGI keyboard             */
+       };
+
+       return memchr(keyboard_ids, id_byte, sizeof(keyboard_ids)) != NULL;
+}
+
+/*
+ * ps2_adjust_timeout() is called after receiving 1st byte of command
+ * response and tries to reduce remaining timeout to speed up command
+ * completion.
+ */
+
+static int ps2_adjust_timeout(struct ps2dev *ps2dev, int command, int timeout)
+{
+       switch (command) {
+               case PS2_CMD_RESET_BAT:
+                       /*
+                        * Device has sent the first response byte after
+                        * reset command, reset is thus done, so we can
+                        * shorten the timeout.
+                        * The next byte will come soon (keyboard) or not
+                        * at all (mouse).
+                        */
+                       if (timeout > msecs_to_jiffies(100))
+                               timeout = msecs_to_jiffies(100);
+                       break;
+
+               case PS2_CMD_GETID:
+                       /*
+                        * If device behind the port is not a keyboard there
+                        * won't be 2nd byte of ID response.
+                        */
+                       if (!ps2_is_keyboard_id(ps2dev->cmdbuf[1])) {
+                               serio_pause_rx(ps2dev->serio);
+                               ps2dev->flags = ps2dev->cmdcnt = 0;
+                               serio_continue_rx(ps2dev->serio);
+                               timeout = 0;
+                       }
+                       break;
+
+               default:
+                       break;
+       }
+
+       return timeout;
 }
 
 /*
@@ -117,7 +177,12 @@ int ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
                return -1;
        }
 
-       down(&ps2dev->cmd_sem);
+       if (send && !param) {
+               WARN_ON(1);
+               return -1;
+       }
+
+       mutex_lock_nested(&ps2dev->cmd_mutex, SINGLE_DEPTH_NESTING);
 
        serio_pause_rx(ps2dev->serio);
        ps2dev->flags = command == PS2_CMD_GETID ? PS2_FLAG_WAITID : 0;
@@ -150,33 +215,7 @@ int ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
 
        if (ps2dev->cmdcnt && timeout > 0) {
 
-               if (command == PS2_CMD_RESET_BAT && timeout > msecs_to_jiffies(100)) {
-                       /*
-                        * Device has sent the first response byte
-                        * after a reset command, reset is thus done,
-                        * shorten the timeout. The next byte will come
-                        * soon (keyboard) or not at all (mouse).
-                        */
-                       timeout = msecs_to_jiffies(100);
-               }
-
-               if (command == PS2_CMD_GETID &&
-                   ps2dev->cmdbuf[receive - 1] != 0xab && /* Regular keyboards */
-                   ps2dev->cmdbuf[receive - 1] != 0xac && /* NCD Sun keyboard */
-                   ps2dev->cmdbuf[receive - 1] != 0x2b && /* Trust keyboard, translated */
-                   ps2dev->cmdbuf[receive - 1] != 0x5d && /* Trust keyboard */
-                   ps2dev->cmdbuf[receive - 1] != 0x60 && /* NMB SGI keyboard, translated */
-                   ps2dev->cmdbuf[receive - 1] != 0x47) { /* NMB SGI keyboard */
-                       /*
-                        * Device behind the port is not a keyboard
-                        * so we don't need to wait for the 2nd byte
-                        * of ID response.
-                        */
-                       serio_pause_rx(ps2dev->serio);
-                       ps2dev->flags = ps2dev->cmdcnt = 0;
-                       serio_continue_rx(ps2dev->serio);
-               }
-
+               timeout = ps2_adjust_timeout(ps2dev, command, timeout);
                wait_event_timeout(ps2dev->wait,
                                   !(ps2dev->flags & PS2_FLAG_CMD), timeout);
        }
@@ -190,12 +229,12 @@ int ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
 
        rc = 0;
 
-out:
+ out:
        serio_pause_rx(ps2dev->serio);
        ps2dev->flags = 0;
        serio_continue_rx(ps2dev->serio);
 
-       up(&ps2dev->cmd_sem);
+       mutex_unlock(&ps2dev->cmd_mutex);
        return rc;
 }
 
@@ -247,7 +286,7 @@ int ps2_schedule_command(struct ps2dev *ps2dev, unsigned char *param, int comman
 
 void ps2_init(struct ps2dev *ps2dev, struct serio *serio)
 {
-       init_MUTEX(&ps2dev->cmd_sem);
+       mutex_init(&ps2dev->cmd_mutex);
        init_waitqueue_head(&ps2dev->wait);
        ps2dev->serio = serio;
 }